"Any Position"
That leaves a lot open.
A primer bulb needs to be installed in the fuel line with the arrow pointed towards the motor. It should also ideally be mounted vertically, with the arrow pointed towards the sky, which allows the weight of the fuel, and gravity inside the bulb to help with the one way valve operation. Most guys just put the bulb on, and it works laying on its side. But if it becomes inverted, with the arrow pointing down, the priming operation will not work as designed, and can cause problems with the fuel flow, which will stop a trip at the dock, or on the water, requiring a tow, for such a simple fix.